This invention generally relates to information recording disk players, and more particularly, the present invention relates to the mechanical structure of a player for information recording disks, such as video disks.
Information recording disk players for reproducing video and/or audio signals from a disk are becoming popular. In such a disk player, a turntable is provided to rotate a disk at a given speed, and a pickup is arranged to trace the tracks on the disk. Since the turntable rotates at a very high speed, for instance 900 rpm, and the density of the tracks is extremely high compared to conventional phonograph records, it is necessary to accurately control various mechanisms. In order that the mechanisms of the player are accurately controlled, respective parts are accurately kept on a chassis with high precision. To this end conventional video disk players employ a chassis made of a diecasting. Although diecasting-made chassis are advantageous because of its rigidity, use of a such a chassis resulted in a heavy player. Furthermore, the conventional diecasting-made chassis are expensive, and it took a relatively long period of time for forming such a conventional diecasting-made chassis. If it is possible to make a chassis by using a synthetic resin, a chassis which is light in weight and low in cost can be obtained. However, most synthetic resins are apt to shrink or contract when being hardened, and therefore, sufficient accuracy in size and relative positional relationship between various parts mounted on the chassis cannot be obtained. Furthermore, since synthetic resins are not rigid as a metal, such a chassis made of a synthetic resin is apt to be curved or bent when various parts are mounted. For these reasons, synthetic resins have not been used as a material for a chassis of a video disk player or the like.
In addition to the above-described problem of the heavy chassis, conventional video disk players have suffered from a problem of irradiation of spurious electromagnetic waves which may cause a television set to be undesirably affected inasmuch as the casing of the player was made of a synthetic resin. Therefore, the conventional video disk players had to be placed, in use, apart from a television set.
Furthermore, conventional disk players had another disadvantage that an intermediate product of the player having only mechanical systems had to be assembled with electrical circuits with the aid of a stand which is temporarily attached to the chassis to hold the same horizontally so that various mechanisms already attached to the chassis are not damaged. In the same way, adjustment of various mechanisms and circuits had to be performed with the aid of the stand.